Fork spring compressed length
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73 gaps at approx 1.9 = 140mm - 5.46 inch of compressable length. plus or minus 1mm. subtract that from stock length.
Length of spring ,compress's more with time! I will explain this, a New spring compress's less than a old one, Reason is as the spring compress's it buckels" SNAKE'S "in the stanchion as the spring wears its sides , :shock: the SNAKE gets more bendy...its very little ..but a fact. :shock: Its like kinking a solid bar down its length. larger the kinks ..shorter it becomes.
Length of spring ,compress's more with time! I will explain this, a New spring compress's less than a old one, Reason is as the spring compress's it buckels" SNAKE'S "in the stanchion as the spring wears its sides , :shock: the SNAKE gets more bendy...its very little ..but a fact. :shock: Its like kinking a solid bar down its length. larger the kinks ..shorter it becomes.
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john robert bould said:
The Commando stanchions should bottom out in the sliders at approximately [Edit 4.5"] of compression travel, so theoretically, standard springs shouldn't become coil-bound with the standard damper/rod assembly.
[Edit: The "Total Fork Movement" figure of "6 in." given in the factory manual is misleading, as the damper assemblies reduce the total stanchion/slider movement by more than 1 inch]
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Thanks
I measure the top of the damper tube collar at about 14.5" from the top of the fork tube compressed, minus 1" with the steel washer, lock nut and top nut intalled give about 13.5" roomfor the spring when the forks are bottomed. So the figure of 13.465" spring compression length is pretty close to coil bind - which is OK if the lower hydraulic stop is the late style or upgraded. Bottom hydraulic lock is stiff for about ½”
I measure the top of the damper tube collar at about 14.5" from the top of the fork tube compressed, minus 1" with the steel washer, lock nut and top nut intalled give about 13.5" roomfor the spring when the forks are bottomed. So the figure of 13.465" spring compression length is pretty close to coil bind - which is OK if the lower hydraulic stop is the late style or upgraded. Bottom hydraulic lock is stiff for about ½”
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Realizing that we are talking end of Golden ear Brit Iron plus there's a few variables in assembly like how tight ya nip down the pre load nut on spring. Spring length or bind does not limit the factory restricted compression travel to engage hard hit bottom stop or the soft 'corrected' factory bottom hydraulic stop. Spring don't limit fork extension either if nothing solid hits, but does run out of spring length expansion after 5" of expansion.
Bush to bush 158.0mm/6.22" = possible travel w/o damper cap in the way.
Top stop (piston) 30.0mm/1.18"
Lower bump stop 23.5mm/.922"
Working length 104.5mm/4.11" as issued, but can be set up to ~ 4.9"
Spring relaxed length 475mm/18.687"
Spring coil bind length 13.476mm/5.21"
Bush to bush 158.0mm/6.22" = possible travel w/o damper cap in the way.
Top stop (piston) 30.0mm/1.18"
Lower bump stop 23.5mm/.922"
Working length 104.5mm/4.11" as issued, but can be set up to ~ 4.9"
Spring relaxed length 475mm/18.687"
Spring coil bind length 13.476mm/5.21"
Mr Hobot is absolutely correct relative to the variance. I don't have the production drawings so keep in mind that I am only offering what I have measured and it may not be per the book per se, but my measurements are accurate. Before I started on this Norton thing that we all catch I had a few spare shillings for drink but have retaken the pledge since the spare goes toward the Norton affliction. Can't afford both, not to the same extent. So I can read the verniers again clearly but the variance from mean may be of importance to you should the design not be accommodating for such.
Working from an old 2D model here I have 14.245 to top of the main stantion from the spring locating shoulder on the dampner tube cap, this is with the main stantion itself bottomed against the inner end of the slider hole, that puts the spring into solid coil bind about 1/4 inch ago. I do have the fibre washer between the tube and slider.
The dampner rod assembly will top out and contact the cap, we know that, the rod moves with the top nut, we know that too, the clock holder also affects the rod position and this has been negated in the discussion so far. We have the thick washer, the locking nut, the clock holder, the trim washer, finally the top nut.
The 1" roughly to the spring from the top of the stantion is a pretty good number.
It's fun going through this stuff, I digest more and overlook less every time I look at it. What are the (2) slots in the end of the stantion of use for?
I do really wish the forum was more categorized, like a topic section for each subsystem but I suppose that's where the search function becomes of use. We do end up with a myriad of threads covering the same topics though.
All the best.
Working from an old 2D model here I have 14.245 to top of the main stantion from the spring locating shoulder on the dampner tube cap, this is with the main stantion itself bottomed against the inner end of the slider hole, that puts the spring into solid coil bind about 1/4 inch ago. I do have the fibre washer between the tube and slider.
The dampner rod assembly will top out and contact the cap, we know that, the rod moves with the top nut, we know that too, the clock holder also affects the rod position and this has been negated in the discussion so far. We have the thick washer, the locking nut, the clock holder, the trim washer, finally the top nut.
The 1" roughly to the spring from the top of the stantion is a pretty good number.
It's fun going through this stuff, I digest more and overlook less every time I look at it. What are the (2) slots in the end of the stantion of use for?
I do really wish the forum was more categorized, like a topic section for each subsystem but I suppose that's where the search function becomes of use. We do end up with a myriad of threads covering the same topics though.
All the best.
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Aw what's a silly mm or 2 plus a displaced decimal among friendly Nortoneers : )
I'm confused on what you are trying to figure this out for?
Its been about a decade since Bob Davis OZ rider and me Ozark rider figured out the whole scope of Roadholders issued to come to conclusion Norton was just using up old stock of springs or stealing from a new vendor order they couldn't reorder w/o paying up first.
W/o the damper cap on or the damper valve on, the forks suddenly get 6+ inches freedom bush to bush but too short a spring by about 1.5" worth to take up the extension slack. A solid spacer also makes the coils bind before gaining travel over factory fault on compression. What ya do then varies, place solid spacer like most or spring spacer like me. The solid spacers like Convent give soft hydro top stop by covering stanchion holes at about the same extension travel of factory issue while the spring spacer stops it as softly at about 1.5+" further extension. The stock top bushes are long enough to do this.
Playing with spring spacer tension or putting a series of different springs in, changes the spring rates to as progressive stiff or soft as ya like. In Peel I got ~1" above and below resting-riding sag level [2" up/down grace range] that is rather soft easy motion, so hardly feel most of THE Gravel rock texture. Then stiffens up greatly the last 1" before bottoming or topping, so hardly ever can, unless hitting limbs or holes at speed. Rather better than the 350 modern dirt bike I tried, poor poggo-ing cripple. Road bikes don't need no 6" travel so both paths above are reasonable, just not for off roading or spanking low down lean limited moderns in the tights. The non foul lean angle goes up when fork extension is increased.
BTW lean angle don't really determine the radius of a turn, so much as how fast ya can take the radius w/o flying up or over. I think I get away w/o much rebound dampening in Peel because she hooks up so well she keeps the front tire lifted out of much traction effect and forks at full extension on turns. This means rather faster into and out of turns than racers do that you see loosing the front because they ain't able to power lift front out of its 'countra' steering effect so every little wind puff and road texture makes the front want to follow that instead of the line you want or the leaned rear thrust demands w/o interference. I see forks as a mere rudder now that merely helps aim whole bike and can be ignored if the powered tire and lean/falling over can do it even better. Then you can no longer straight steer and expect not to fly off its tangent. Must change riding philosophy or crash which is why I can't study race video except to see how it goes wrong in phase 2 turning.
Alas the factory spring suck as concerns their spring rate, rather too stiff for the little stuff and too weak for the harsher stuff like panic braking. I lucked out to snag the last of a custom 4 rate batch developed by Paul Geoff.
http://www.norbsa02.freeuk.com/
That alone made a nice improvement but Peels 'miracle' forks didn't do their full magic till steeply progressive valve spring spacer used. I lucked out 2nd time with the 2" longer 10 mm OD Al rods that took up most the damper cap ID so sanded down a 2" long waist in the rod so traps fork fluid less than factory within 2" centered travel yet resists motion more than factory on the extra 2" extension and extra 2" compression. Its was cheap and simple hick way some years before Landowne [sp] kit became available and only a super expensive cartridge was being sold that needed sliders machined to accept.
I suspect the rebound dampening is more important than the compression dampening as fork expands when ever bike tipped over whether on power or not, but will compress on trail braking as seems all corner cripples tend to do before apexes. To me the most dangerous low traction state you can put a bike into, duh. I never ever do that after THE Gravel teacher spanked me so hard on its limitations.
Even with great internals at some turning-fling-reversing-rates-loads, the forks twist up to delay then magnify pilot input to feel life rubber bands connect grips to tire patch and fling bike the wrong way at the wrong time the wrong amount terrifyingly, especially on un-tamed isolastic chassis rebounders. RGM no longer sells their brace that helps over lap fork support on full 6" extension so there's a needed item to re-develop to replace it.
I'm confused on what you are trying to figure this out for?
Its been about a decade since Bob Davis OZ rider and me Ozark rider figured out the whole scope of Roadholders issued to come to conclusion Norton was just using up old stock of springs or stealing from a new vendor order they couldn't reorder w/o paying up first.
W/o the damper cap on or the damper valve on, the forks suddenly get 6+ inches freedom bush to bush but too short a spring by about 1.5" worth to take up the extension slack. A solid spacer also makes the coils bind before gaining travel over factory fault on compression. What ya do then varies, place solid spacer like most or spring spacer like me. The solid spacers like Convent give soft hydro top stop by covering stanchion holes at about the same extension travel of factory issue while the spring spacer stops it as softly at about 1.5+" further extension. The stock top bushes are long enough to do this.
Playing with spring spacer tension or putting a series of different springs in, changes the spring rates to as progressive stiff or soft as ya like. In Peel I got ~1" above and below resting-riding sag level [2" up/down grace range] that is rather soft easy motion, so hardly feel most of THE Gravel rock texture. Then stiffens up greatly the last 1" before bottoming or topping, so hardly ever can, unless hitting limbs or holes at speed. Rather better than the 350 modern dirt bike I tried, poor poggo-ing cripple. Road bikes don't need no 6" travel so both paths above are reasonable, just not for off roading or spanking low down lean limited moderns in the tights. The non foul lean angle goes up when fork extension is increased.
BTW lean angle don't really determine the radius of a turn, so much as how fast ya can take the radius w/o flying up or over. I think I get away w/o much rebound dampening in Peel because she hooks up so well she keeps the front tire lifted out of much traction effect and forks at full extension on turns. This means rather faster into and out of turns than racers do that you see loosing the front because they ain't able to power lift front out of its 'countra' steering effect so every little wind puff and road texture makes the front want to follow that instead of the line you want or the leaned rear thrust demands w/o interference. I see forks as a mere rudder now that merely helps aim whole bike and can be ignored if the powered tire and lean/falling over can do it even better. Then you can no longer straight steer and expect not to fly off its tangent. Must change riding philosophy or crash which is why I can't study race video except to see how it goes wrong in phase 2 turning.
Alas the factory spring suck as concerns their spring rate, rather too stiff for the little stuff and too weak for the harsher stuff like panic braking. I lucked out to snag the last of a custom 4 rate batch developed by Paul Geoff.
http://www.norbsa02.freeuk.com/
That alone made a nice improvement but Peels 'miracle' forks didn't do their full magic till steeply progressive valve spring spacer used. I lucked out 2nd time with the 2" longer 10 mm OD Al rods that took up most the damper cap ID so sanded down a 2" long waist in the rod so traps fork fluid less than factory within 2" centered travel yet resists motion more than factory on the extra 2" extension and extra 2" compression. Its was cheap and simple hick way some years before Landowne [sp] kit became available and only a super expensive cartridge was being sold that needed sliders machined to accept.
I suspect the rebound dampening is more important than the compression dampening as fork expands when ever bike tipped over whether on power or not, but will compress on trail braking as seems all corner cripples tend to do before apexes. To me the most dangerous low traction state you can put a bike into, duh. I never ever do that after THE Gravel teacher spanked me so hard on its limitations.
Even with great internals at some turning-fling-reversing-rates-loads, the forks twist up to delay then magnify pilot input to feel life rubber bands connect grips to tire patch and fling bike the wrong way at the wrong time the wrong amount terrifyingly, especially on un-tamed isolastic chassis rebounders. RGM no longer sells their brace that helps over lap fork support on full 6" extension so there's a needed item to re-develop to replace it.
L.A.B. said:
How did you arrive at the 1/4"coil bind figure?
14.245 is to the top of the main stantion. The spring is held approximately one inch below that by the fixing hardware.
14.245 minus 1 is 13.245 or thereabouts.
The spring goes solid at 13.465.
Therefore 13.465 minus 13.245 is around 1/4 inch beyond the solid.
Clearer now?
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If you only have 1/4 of coil bind -then you're already 1/4" into the hydraulic bottom bump stop. You can alway use thinner top spring washers, or remove them and drill/thread smaller 5/16 nuts out to 3/8 to fit on the damper rods and inside the springs.
I'm going throuh all this to work out measurements for the alum sleeves that give hydraulic stops top & bottom.
To go with the Turcite bushings.
I'm going throuh all this to work out measurements for the alum sleeves that give hydraulic stops top & bottom.
To go with the Turcite bushings.
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Hi there, maybe it's already known , but in the case it's not , here is a link/
http://www.members.shaw.ca/randell/roadholders.html
Pierre
http://www.members.shaw.ca/randell/roadholders.html
Pierre
Sorry but I'm not calculating that. Perhaps I've somehow misled you.L.A.B. said:
I'm just responding to the post by Jseng that stated the length from the spring seating on the dampner cap was (some distance) to the top of the stantion when the stantion is bottomed out into the slider.
If that (some distance) minus 1" is less than the spring solid height there will be spring bind. That's all.
I measure full travel at approximately 4.85", this is the mechanical travel possible for the stock assembly with only the spring taken out of the picture. It cannot be achieved however with the spring in place. With the spring in place the mechanical travel is limited to around 4.63" because the spring will go solid. At my house it does.
Is this of any help?
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AntrimMan said:
It is almost clearer. I have a completely machine sectioned away demo commando fork leg assembly to be able to give tech sessions and view the components in real world and then when installed with a commando triple tree with commando clock holder/washer, on mine it does not measure out that the spring goes coil bound.
http://atlanticgreen.com/forks.htm
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I relate to that and as Jim says to avoid it one should get the bottoming hydraulic stopper working by the eons old moving damper holes up above the tapper, which is the .922" useless wishful thinking listed bottom travel length. I shorted Peels up to ~3/4" with staggered holes and truly can not feel a solid bottom - just indefinite reversal of fork motion. If ya don't stop by 'soft' hydraulic lock up then it hits solid on coil bind. Leaving space at top of spring also avoid this but then leave slack on top out length, which ain't much as issue actually, just wastes some spring force space to help resist fork compression more controlled.
With the extra spring space in there one can thread the [longer] damper rod further down so nut can set sag factor some.
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